Thanks Nigel. There are some difference between the two's playback engine. The MTPro seems a little more authentic to me, I was brought up listening to Mellotron's Mood Blues, King Crimson, Yes, etc. I also wanted to experiment with comparing the two. You might of guessed the whole base of this tune is around vocal's, with only the OB-E providing some bass, the PS-20 providing the slightly off/jarring ARP pattern, the Voltage Modular providing the surf adding any other sound to it.
Again thanks for the ears, time and comments as always they are greatly appreciated.